Low-dose aspirin may block the growth and spread of breast cancer, new research suggests.
The painkiller appears to prevent the creation of resistant stem cells that drive the disease.
University of Kansas scientists made the discovery after laboratory tests showed that aspirin directly and indirectly suppressed the proliferation of two different breast cancer strains.
One was so-called 'triple negative' breast cancer which is immune to many treatments.
Aspirin also boosted the effect of tamoxifen, a widely used treatment for the more common form of the disease stimulated by the hormone oestrogen.
As well as putting a brake on breast cancer in lab dishes, aspirin significantly reduced its growth in mice.